// Copyright [2020] <unknown>
#include <bits/stdc++.h>
using namespace std;
// #define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#define dbg(x...) { cerr << "\033[32;1m" << #x << " -> "; err(x); }
void err() { cerr << "\033[39;0m" << endl; }
template<typename T, typename... A>
void err(T a, A... x) { cerr << a << ' '; err(x...); }
#else
#define dbg(...)
#endif

#define sz(x) ((int)x.size())

typedef long long LL;

int t, n;
int x, a, b;
int main(int argc, char const *argv[]) {
    scanf("%d", &t);
    for (int kk=0; kk<t; ++kk) {
        scanf("%d%d%d%d", &n, &x, &a, &b);
        if (a > b) swap(a, b);
        int y = min(a-1, x);
        x -= y;
        a -= y;
        y = min(n - b, x);
        x -= y;
        b += y;
        printf("%d\n", b-a);
    }
    // code
    return 0;
}
